The Influence of Lubricant Rheology on Friction in the Piston Ring-Pack

Approximate numerical method for lubrication with Generalised Newtonian fluids

“…In addition to this a comparison was also made with the pressure field from an adapted form of Reynolds equation where the local fluid viscosity is a function of the average shear rate (details on this can be found in references [9,10,12,13]). It can be seen by comparing figures 3a and 3b that the predictions from the 4th order viscosity function are significantly better than those from the average shear based viscosity results, which gives percentage errors 2-3 times greater than the 4th order viscosity function based solution.…”

In-situ piston measurements

“…A range of experiments was carried out, varying the engine speed and load. Results from these experiments have been reported fully elsewhere [26,27]. However, it is worth reporting results on the variation in top-ring OFT with lubricant viscosity grade, which were not included in the previous publications.…”

“…A number of groups have carried out OFT measurements in a piston ring pack, some using electrical techniques [17][18][19][20][21], while others have used laser-induced fluorescence (LIF) techniques [22][23][24][25][26][27]. Our initial experiments used a window machined into the cylinder liner.…”

Analytical and numerical solutions of thin lubricating films for differing shear-thinning viscosity models

“…However, even when one ignores the subtleties of the elastic deformation of bounding surfaces, which may occur in conditions of heavy loading [10], the fluids involved in tribological applications often exhibit various non-Newtonian behaviour. Not surprisingly, this has led to a body of work directed at incorporating such effects, a major one of which being shear-thinning [11][12][13][14][15], within a lubrication framework.…”